Spring retainer for balancers



July; 3, 1951 E. w. STEVENS 2,559,264

SPRING RETAINER FOR BALANCERS Original Filed June 27, 1939 3 Sheets-Sheet 1 INVENTOR Edward W5zevens WORNEY July 3, 1951 l E. w. STEVENS 2,559,264

SPRING RETAINER FOR BALANCERS ori inal Filed June 27, 1959 3 Sheets-Sheet 2 INVENTOR Edward M1 32% Vans ATTORNEY July 3, 1951 E. w. STEVENS 2,559,264 SPRING RETAINER FOR BALANCERS Original Filed June 27, 1939 3 Sheet's-Sheet 3 Patented July 3, 1951 SPRING RETAINER FOR BALANCERS Edward W. Stevens,

Chicago Pneumatic N. Y., a corporation Detroit, Mich., assignor to Tool Company, New York, of New Jersey Original application June 27, 1939, Serial No.

281,370. Divided and ber 15, 1943, Serial No.

2 Claims.

'1 This invention relates generally to weight balancing devices of the spring counterbalancing type and more particularly to certain improvements in-spring retainers facilitating assembly or handling of the counterbalancing spring thereof. 5 moving the present spring assembly, nor is it This application is a division of copending applinecessary to remove the balancer from its support cation Serial No. 281.370, filed June 27, 1939, now or detach the suspended load at this time. The Patent No. 2,342,020 .granted February 15, .1944. construction of the spring retainer is thought to The improvements of the present invention are present a particularly novel and desirable feature disclosed as embodied in a counterbalancer of in that its inner surface is formed with a pluthe kind most commonly used in the suspension rality of individual contact .points so that the of a pneumatic tool, or like article, from an overspring is engaged only by these several points and head support. The function of the balancer is is spaced a short distance away from the main to equalize the pull of gravity upon the suspended surface of the retainer. Such an arrangement tool or other load to permit a greater ease of greatly facilitates the removal of a broken spring manipulation of the tool and to facilitate its from the retainer since the several coils of the movement to and from working position. The spring may more easily be clamped together bemode of operation of the usual balancer and the fore the spring is removed. v essential elements comprised therein are well The broad object of this invention is to proknown to those skilled in the art. Included in duce a spring counterbalancer having the imthese elements is a rotatable drum or reel, upon proved construction discussed above. which the suspension cable is wound, and a coil More specifically, an object of the invention is spring which tensions the drum in a direction to simplify the mounting of a counterbalancing opposite to that in which it must turn to pay spring to render it more readily accessible for purout the cable. Also, a means is customarily proposes of replacement. vided for adjusting the spring to an initial ten- Another object of the invention is to enclose sion which is suificient to balance the suspended the spring in a retainer of novel construction load in one position. A particular difiiculty ento form thereby a spring assembly which may be countered in assembling and disassembling the shipped, stored and mounted on the balanceras majority of balancers used heretofore is the hana unitary element. dling of the coil spring. In the usual balancer Other objects and structural features of the inthe spring is inserted in acontainer-formed intevention will be more apparent from the followin grally with the frame work of the balancer or, in detailed description, when read in connection some cases, is positioned in the drum itself. Apart With he a o pany drawings, w r n! from the well recognized fact that handling of a Fig. 1 is a side View, partly in elevation and heavy coiled spring is always a hazardous underp r ly in se n. of a l n m yin h taking, the insertion and removal of a spring so invention; positioned has another disadvantage in that it F s a persp v View Of the presentbalnecessitates at least a partial disassembly of the ancer drawn on a reduced scale; balancer. It is not an uncommon occurrence for Figs. -3 and 4 are elevations of the spring assema spring to break while in use. When such breakbly as mounted upon the balancer, Fig. 3 showage occurs the balancer is out of use for the rather ing the normal condition of the spring when considerable time necessary for a mechanic to wound to initial tension, and Fig. 4 the condition replace the broken spring with a new one. of the spring when broken; and

It was with the object in view of simplifying Fig. 5 is a sectional view showing a portion of the handling, insertion and removal of a balancer the balancer as modified for use with two spring spring that the present spring retainer has been assemblies. developed. This retainer consists of a ring which Referring first to Figs. 1 and 2, itwill be seen encloses the spring and which forms, in comthat the principal supporting elements of the balbination with the spring, a unitary spring assemancer are an outer housing I, a central bracket bly. The spring and its retainer are shipped and 2 and a shaft 3 (Fig. 1). The housing I and stored as an assembly and are mounted on the bracket 2 are rigidly secured together by screws balancer in the same manner. The present bal- A (Fig. 2) and by tie rods 5 which serve the addiancer is so constructed as to .provide a mounting tional function of supporting a ball bearing socket for the spring assembly which is entirely inde- 6 in which :is mounted the usual swivel hook I this application Decem- 514,342

pendent of the cable drum and which renders the assembly easily accessible for replacement. It is unnecessary to disassemble the balancer mechanism even partially when inserting or rebracket and projecting laterally therefrom.

through and beyond the bracket 2.

housing I and bracket 2, is the cable drum II.

This drum is generally similar to the drum disclosed in the patent to W. H. Benedict, No. 1,794,825, issued March 3, 1931. The drum is preferably constructed as a single piece, is generally conical in shape and formed in its outer surface is a spiraled groove I2 which guides the cable I3.

The sprin retainer I4 which forms a part of the spring assembly, is shown in Fig. 1 as positioned to the right of supported by a plurality of posts I5 set in the In the device shown there are three such posts I5, spaced equal distances apart and. positioned near the ring of the bracket (see Fig. 2). retainer consists primarily of a retaining element in the form of a simple ring which can be placed inside the posts I5 and held flush against the bracket 2 by a cover I6 bolted to the. posts I5. however, has, in addition to the ring I4, an inner lining strip H (see Figs. 3 and 4) fixed to the inner surface of the ring and bent inward, at spaced intervals, to provide a series of contact- The retainer shown in the drawings, 3

the central bracket 2 and The points IS in the form of semi-loops. A coil spring 35 I9 is mounted within the retainer. When the sprin I9 is in completely expanded position, the outer coil thereof engages merely the several contact points I8, and is spaced a short distance away from the relatively flat portion 40 between the spring and the retainer is reduced to a minimum. With further regard to the construction of the spring retainer, it will be apparent that the linin strip I I is used here merely as a mechanical expedient since the ring I4 could itself be quite easily formed with contact points I8 and a retainer of one piece construction thus produced.

Considering now the manner of tensioning the spring I9, it will be observed that the outer The inner end of the spring engages a groove cut in a collar 22 surroundin the right-hand or outer end of the shaft 3 which, as is shown in Fig. 1, extends,

end of the shaft 3 and the inner surface of the collar 22 are substantially oval in shape, the arrangement being such that the collar is forced to rotate with the shaft but may be moved relaend of the spring is fixed to an anchor post 2| 'set in the fixed bracket 2.

The outer tively thereto in a longitudinal direction during assembly or disassembly. It will thus be seen that movement of the shaft 3 in a counterclockwise direction, as viewed in Figs. 3 and 4, will wind or tension the spring I9, the amount of tension depending on the position of the Shaft 3 relative to the fixed housing I. A is well known in the art, a preliminary to the operation of a spring balancer is the setting of the spring to a minimum or initial tension, which tension is of course determined by the weight of the article intended to be balanced or suspended. This setting of the spring is done by hand and is accomplished, in the present instance, by turning the shaft 3 relative to drum II while the latter is held immovable at the extreme limit of its cable winding movement. The adjustment is effected by a worm 23 (Fig. l) which engages a worm gear 24 fast on the shaft 3 near its lefthand end. The worm 23 is positioned in a channel in the cable drum II and has, on its outer end, a head (not shown) which may be engaged by a crank to rotate the worm, the gear 24, and the shaft 3 to tension the spring I9 the desired minimum amount. The worm cannot, of course, beturned by the worm gear, so that although the springtension may be increased by rotation of the cable drum in the load lowering direction, it cannot be reduced below the initial amount except by manual rotation of the crank, or upon breakage of the spring.

As the drum II rotates, therefore, to pay out the cable I3 and lower the suspended article, it carries shaft 3 inunison therewith in a counterclockwise direction (Fig. 3), and further tensions the spring I9. An approximately uniform balancing force is maintained notwithstanding the increasing tension of the spring, by reason of the progressively greater leverage afforded by the gradually increasing diameter of the cable groove I2. This subject of balance and balance range is considered in greater detail in the previously mentioned patent to Benedict. Return of the cable drum to normal will,.of course, un-

wind the spring to its initial tension.

During the operation of the balancer the spring I9 winds and unwinds to and from its initial position of Fig. 3, but if during the course of such operation the spring should break, it would immediately expand to the position disclosed in Fig. 4. In both Figs. 3 and 4 is shown how the inwardly bent and spaced points or projections IB on strip I! provide convenient clearance spaces between'the spring and the strip and the spring retainer or barrel I4, so as to allow access to the outside of the spring for retaining a grip on the latter when the same is to be replaced. As the outer end is readily slipped off from the anchor post 2I and the inner end with the collar 22 has easily slipped off from shaft 3, it is evident that removal and replacement of the spring may readily be accomplished.

, An important feature of the present balancer is the ease with which it may be adaptedfor use with a plurality of spring assemblies. In Fig. 5 is shown a section of a balancer modified by having two springs I 9 enclosed by separate spring retainers I4. To accommodate the additional spring retainer it is merely necessary to lengthen the shaft 3, as well as supporting posts I5, etc. It will be noted that each retaining ring. I4 is of slightly greater width than the spring which it encloses. This construction renders the handling of a spring assembly easier and safer and anchor means at its outer end to anchor said end with respect to the retainer element to prevent relative movement therebetween when the assembly is in operative use, and an anchor means on the inner end of the spring to couple with a relatively movable element, said retainer element being of greater width than the spring and having several contact points projecting inwardly from the surface thereof, said contact points being spaced circumferentially so that the distance between any two adjacent contact points is substantially less than 180 and being further arranged to engage the outer coil of the spring and maintain the latter in spaced relationship to the retainer element so that tool means can be clamped about the spring from either side of the retainer element and at various points of the spring periphery between the contact points while the spring is positioned within the retainer element.

2. An assembly comprising an open sided retainer element, a lining strip mounted on the inner surface of the retainer element, and a spirally coiled spring positioned within the retainer element and having anchor means at its outer end to anchor said end with respect to the retainer element to prevent relative movement therebetween when the assembly is in operative use, and an anchor means on the inner end of the spring to couple with a relatively movable element, said retainer element being of greater width than the spring, said lining strip having several contact points extending inwardly relative to the retainer element and being spaced circumferentially so that the distance between any two adjacent contact points is substantially less than and further adapted to engage the outer coil of the spring and maintain the latter in spaced relationship to the retainer element so that tool means can be clamped about the spring from either side of the retainer element and at various points of the spring periphery between the contact points while the spring is positioned within the retainer element.

EDWARD W. STEVENS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 296,738 Fawkes Apr. 15, 1884 774,525 Mack Nov. 8, 1904 915,288 Hagstrom Mar. 16, 1909 1,138,738 Earll May 11, 1915 1,645,254 Pederson Oct. 11, 1927 1,677,045 Odom July 10, 1928 2,078,489 Forss Apr. 27, 1937 2,094,182 Nash Sept. 28, 1937 2,342,020 Stevens Feb. 15, 1944 

